verb vs linking verb

verb and linking verb both are nouns.

Word	Noun	Adjective	Verb	Adverb
verb	Yes	No	No	No
linking verb	Yes	No	No	No

As nouns, linking verb is a hyponym of verb; that is, linking verb is a word with a more specific, narrower meaning than verb:

verb: a content word that denotes an action, occurrence, or state of existence
linking verb: an equating verb (such as `be' or `become') that links the subject with the complement of a sentence

verb (noun)	linking verb (noun)
a content word that denotes an action, occurrence, or state of existence	an equating verb (such as `be' or `become') that links the subject with the complement of a sentence
the word class that serves as the predicate of a sentence